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September 2013 - present
February 2003 - November 2007
Publications
Publications (47)
Populations of several species of birds endemic to the Galápagos Islands have declined during recent decades, including endemic Little Vermilion Flycatchers (Pyrocephalus nanus). Understanding the reasons for the low breeding success of this species is a prerequisite for developing efficient conservation strategies. Studies of sympatric Darwin's fi...
Populations of several species of birds endemic to the Galápagos Islands have declined during recent decades, includingendemic Little Vermilion Flycatchers (Pyrocephalus nanus). Understanding the reasons for the low breeding success of this species isa prerequisite for developing efficient conservation strategies. Studies of sympatric Darwin’s finc...
Plant-based repellents represent a safe, economic, and viable alternative to managing invasive insects that threaten native fauna. Observations of self-medication in animals can provide important cues to the medicinal properties of plants. A recent study in the Galapagos Islands found that Darwin’s finches apply the leaves of Psidium galapageium (H...
Behavioural endocrinology addresses the changes in perception, cognition and behaviour brought about by hormones. Ejaculation is linked to substantial changes in hormones and leads to complex modifications in behaviour. Increased testosterone levels have been found to be associated with higher levels of aggression, higher sex drive and altered deci...
El bosque de Scalesia, que alberga al más alto número de especies de plantas y animales en Santa Cruz, se ha visto reducido de manera drástica por actividades agrícolas en el pasado y más recientemente por plantas invasoras (Rentería & Buddenhagen, 2006). En Santa Cruz solo quedan 100 ha, menos de 1% de su distribución original, dándose la mayor co...
The Scalesia forest, housing the highest number of plant and animal species in the highlands of Santa Cruz, has been drastically reduced by agricultural activities in the past and more recently, by invasive plants (Rentería & Buddenhagen, 2006). On Santa Cruz, about 100 ha remain, less than 1% of its original distribution, with the largest concentr...
We investigated the role of olfactory cues from actively fermenting yeast (Saccharomyces cerevisiae) in attraction of adult Philornis downsi and identified two synergistically attractive yeast volatiles. Larvae of this invasive fly parasitize the hatchlings of passerines and threaten the Galapagos avifauna. Gas chromatography coupled with electroan...
Darwin’s finches are highly innovative. Recently we recorded for the first time a behavioural innovation
in Darwin’s finches outside the foraging context: individuals of four species rubbed leaves of the
endemic tree Psidium galapageium on their feathers. We hypothesised that this behaviour serves to
repel ectoparasites and tested the repellency of...
Animal innovations range from the discovery of novel food types to the invention of completely novel behaviours. Innovations can give access to new opportunities, and thus enable innovating agents to invade and create novel niches. This in turn can pave the way for morphological adaptation and adaptive radiation. The mechanisms that make innovation...
Invasive alien parasites and pathogens are a growing threat to biodiversity worldwide, which can contribute to the extinction of endemic species. On the Galápagos Islands, the invasive parasitic fly Philornis downsi poses a major threat to the endemic avifauna. Here, we investigated the influence of this parasite on the breeding success of two Darw...
Behavioural flexibility is thought to be a major factor in evolution. It may facilitate the discovery and exploitation of new resources, which in turn may expose populations to novel selective forces and facilitate adaptive radiation. Darwin's finches are a textbook example of adaptive radiation. They are fast learners and show a range of unusual f...
The use and manufacture of tools have been considered to be cognitively demanding and thus a possible driving factor in the evolution of intelligence. In this study, we tested the hypothesis that enhanced physical cognitive abilities evolved in conjunction with the use of tools, by comparing the performance of naturally tool-using and non-tool-usin...
The ability to unlearn a previously established association is an important component of behavioural flexibility and may vary according to species ecology. Previously, two closely related sympatric Darwin’s finches were found to differ in their learning abilities. Small tree finches (Camarhynchus parvulus) outperformed woodpecker finches (Cactospiz...
Population monitoring is a vital tool for conservation management and for testing hypotheses about population trends in changing environments. Darwin’s finches on Santa Cruz Island in the Galápagos archipelago have experienced habitat alteration because of human activity, introduced predators, parasites and disease. We used point counts to conduct...
Here we describe the modification and use of a new tool type in the woodpecker finch (Cactospiza pallida). This species is known to habitually use twigs or cactus spines to extract arthropods out of tree holes. We observed an adult and a juvenile bird using several barbed twigs from introduced blackberry bushes (Rubus niveus) which the adult bird h...
The use and manufacture of tools has been considered to be cognitively demanding and thus a possible evolutionary driving factor of intelligence. Animal tool use provides the opportunity to investigate whether the use of tools evolved in conjunction with enhanced physical cognitive abilities. However, success in physical tasks may simply reflect en...
The critically endangered Mangrove Finch (Camarhynchus heliobates) is a habitat specialist restricted to mangroves, with a global population size of about 100 individuals. Due to its extremely limited geographic range and low dispersal capabilities, translocations of individuals to different mangrove areas within its historic range have been consid...
The trap tube is a classic test of causal reasoning abilities in animals in the physical domain. Recently, a modified version of this task improved its diagnostic capacity and allowed testing of non-tool-using animals. We used this modified two-trap tube task to compare the cognition of two Darwin's finch species: the woodpecker finch, Cactospiza p...
Habitat destruction and predation by invasive alien species has led to the disappearance of several island populations of Darwin's finches but to date none of the 13 recognized species have gone extinct. However, driven by rapid economic growth in the Galápagos, the effects of introduced species have accelerated and severely threatened these iconic...
Darwin's finches are a classic example of adaptive radiation. The ecological diversity of the Galápagos in part explains that radiation, but the fact that other founder species did not radiate suggests that other factors are also important. One hypothesis attempting to identify the extra factor is the flexible stem hypothesis, connecting individual...
Introduction: Niko Tinbergen (1963) proposed four levels of analysis in seeking to explain why a given behavior exists: phylogenetic, functional, developmental and mechanistic. He postulated that only the integration of all four levels enables us to fully understand behavior. Animal tool use initially captivated the scientific world because of its...
One of the main functions of exploratory behaviour is to gain information about the environment. The adaptive value of such
behaviour should vary with ecological conditions influencing the diversity and stability of resources, as well as with the
costs associated with gathering information. Consequently, predictions can be made about environmental...
The trap-tube problem is used to assess whether an individual is able to foresee the outcome of its actions. To solve the task, an animal must use a tool to push a piece of food out of a tube, which has a trap along its length. An animal may learn to avoid the trap through a rule based on associative processes, e.g. using the distance of trap or fo...
Although animals (particularly tool-users) are capable of solving physical tasks in the laboratory , the degree to which they understand them in terms of their underlying physical forces is a matter of contention. Here, using a new paradigm, the two-trap tube task, we report the performance of non-tool-using rooks. In contrast to the low success ra...
It is widely recognised that the main threats to the biota of the Galápagos Islands stem from newly introduced diseases, plants and animals. Introduced organisms may lead to the rapid extinction of naïve insular populations. Previous research on Galápagos showed that the parasitic larvae of the fly Philornis downsi occurred in virtually all nests o...
The avian food-caching paradigm has greatly contributed to our understanding of a number of cognitive capacities. Although the early work focused on spatial memory, contemporary studies of the cognitive abilities of food-caching birds have a much broader scope. This chapter describes an approach to the comparative cognition of caching which capital...
Woodpecker finches are famous for their spontaneous tool use behaviour in the wild. They use twigs or cactus spines to pry arthropods out of crevices and use this ability more than any other tool-using species known. We experimentally investigated the cognitive abilities related to tool use. We chose three experimental designs that have been used t...
In the Galapagos Islands climate and food abundance vary strongly among vegetation zones and between seasons. We studied the foraging behavior of four mainly insectivorous Darwin's finch species on Santa Cruz Island. We compared foraging behavior between (1) the arid zone, where food is scarce, with the humid Scalesia zone, where food is abundant;...
The Critically Endangered mangrove finch Cactospiza (=Camarhynchus) heliobates is now confined to Isabela Island in the Galápagos Islands and is exclu-sively found in mangrove forests. Formerly it occurred also on neighbouring Fernandina Island, but is appar-ently extinct there. The population size and ecology of the species was relatively unknown...
The Critically Endangered mangrove finch Cactospiza (=Camarhynchus) heliobates is now confined to Isabela Island in the Galápagos Islands and is exclusively found in mangrove forests. Formerly it occurred also on neighbouring Fernandina Island, but is apparently extinct there. The population size and ecology of the species was relatively unknown un...
Individual recognition has been attributed a crucial role in the evolution of complex social systems such as helping behaviour and cooperation. A classical example for interspecific cooperation is the mutualism between the cleaner fish Labroides dimidiatus and its client reef fish species. For stable cooperation to evolve, it is generally assumed t...
Insects, mammals and birds are known to use tools, but empirical evidence of the ecological importance of tool-use is scarce. Here, we present the first ecological study of tool-use by a bird species. Woodpecker finches use twigs or cactus spines to pry arthropods out of tree-holes. We compared tool-use during wet and dry seasons in two different v...
The obligate dipterian bird parasite Philornis downsi and the facultative parasitic fly Sarcodexia lambens were, until recently, unknown on the Galápagos archipelago. The first sign of parasitism of P. downsi on Darwin's finches was found in 1997. Parasitism data were collected from 177 nests of 12 bird species, including eight endemic species. In...
Tool-use is widespread among animals, but except in primates the development of this behaviour is poorly known. Here, we report on the first experimental study to our knowledge of the mechanisms underlying the acquisition of tool-use in a bird species. The woodpecker finch Cactospiza pallida, endemic to the Galápagos Islands, is a famous textbook e...
Females do not unanimously choose the single ‘best’ male, even when female choice is strong, such as in leks, or in polygynous mating situations. A possible explanation is that females base their choices on limited information, perhaps because gathering information is costly. We tested this hypothesis by continuously observing individual female mar...
Philornis downsi Dodge & Aitken is recorded from the Galapagos Islands for the first time. All the Galapagos bird associations are new records for this species: Camarhynchus parvulus, Camarhynchus psittacula, Cactospiza pallida, Certhidea olivacea, Geospiza fuliginosa, Geospiza fortis (all Fringillidae), Nesomimus parvulus (Mimidae), Dendroica pete...
This study assessed whether keas,Nestor notabilis, are able to cooperate in an instrumental task. Seven birds of a captive group were tested in group situations and in dyads. At least two individuals had to manipulate an apparatus to obtain food but only one participant was rewarded. One bird had to push down a lever to enable another one to collec...
Projects
Projects (4)
The Scalesia forest, housing the highest number of plant and animal species in the highlands of Santa Cruz, has been drastically reduced by agricultural activities in the past and more recently, by invasive plants. One of the worst invasive plants at Los Gemelos is blackberry which grows vigorously and prevents recruitment of native species. Over more than ten years, the Galapagos National Park Directorate (GNPD) has successfully controlled blackberry by applying herbicides.
However, there is concern that this intensive management has changed the structure of the forest, and is impacting the invertebrates and birds that live there. To evaluate this, we assess vegetation composition and insect abundance in two areas, one with a high density of blackberry and the other where the GNPD is actively controlling it.
